1. The sealing gasket and flange sealing cover shall be cleaned and free of any scratches, spots or other defects that affect the sealing performance of the connection.

2. The outer diameter of the sealing gasket shall be smaller than that of the flange sealing cover, and the inner diameter of the sealing gasket shall be slightly larger than that of the pipe.

3. The pre-tightening force of sealing gasket shall not exceed the design specification, so as to avoid over-compression of sealing gasket and loss of resilience.

4. It is better to use torque wrench when sealing gasket is pressed.For large bolts and high strength bolts, it is best to use hydraulic tightening device.The tightening torque should be calculated according to the pressure of the given seal gasket, and the hydraulic pressure of the hydraulic tightening device should also be determined by calculation.

5. When installing sealing gaskets, tighten the nuts in sequence.But should not twist once to achieve the design value.In general, circulation should be at least 2 to 3 times, so that the sealing gasket stress distribution is uniform.

6. For pressure vessels and pipelines with flammable and explosive media, safety tools should be used when replacing sealing gaskets, so as to avoid fire or explosion accidents caused by sparks caused by the tool hitting flange or bolt.[2]

7. If there is any leakage in the pipeline, it shall be replaced or adjusted to install the sealing gasket after the pressure reduction treatment. Pressure operation is strictly forbidden.